Secured Assembly Electrical Apparatus with Interposed Tab

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Solution Overview

Problem

Existing electrical equipment installation methods, such as those using leaf springs or snap tabs, are prone to faulty fixation and do not allow for adjustment of the gap between the cover plate and the electrical box, leading to potential tearing of the socket when removing a plug or adding wall coatings.

Innovation Solution

The electrical equipment design incorporates a tab that presses against a rigid part of the electrical block, ensuring secure locking and preventing inward bending, with the same tab used for both fixing and locking, reducing the number of tabs on the front part and facilitating manufacturing and safety through keying compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If spring-loaded tabs are used to fix the equipment support to the electrical box, then the fixation process becomes simpler, but the reliability of the connection deteriorates because the tabs can bend or fail to engage properly

Engineering Contradiction:
Improveease of installationVSAvoidconnection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The connection system is divided into two independent parts: rigid connection elements (tabs with stops) for secure engagement and flexible elements (spring-loaded clips) for maintaining contact pressure. This segmentation allows each part to perform its specific function optimally without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring-loaded clips act as a cushioning element that compensates for manufacturing tolerances and installation variations. They provide a safety margin that prevents complete disengagement even if the rigid tabs are not perfectly positioned, thereby maintaining connection reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If flexible tabs are used on the cover plate to accommodate wall thickness variations, then the adaptability improves, but the ability to prevent tab bending deteriorates because flexible tabs cannot provide rigid support

Engineering Contradiction:
Improveadjustability to wall thicknessVSAvoidresistance to bending
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The cover plate connection system is segmented into rigid tabs with stops for structural support and bending resistance, and flexible spring-loaded clips for adaptability to wall thickness variations. Each segment performs its specialized function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring-loaded clips serve as intermediary elements between the rigid tabs and the wall cavity. They transmit and distribute forces while accommodating dimensional variations, allowing the rigid tabs to maintain their strength without direct contact with variable wall surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple tabs are used on the front part to ensure secure connection, then the connection reliability improves, but the device complexity increases due to more parts and assembly steps

Engineering Contradiction:
Improveconnection securityVSAvoidnumber of tabs and assembly steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each tab is designed with multi-functionality: the rigid tab provides structural engagement and positioning, the stop prevents over-travel and disengagement, and the spring-loaded clip maintains continuous contact pressure. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple functional elements (tab, stop, spring-loaded clip) are merged into integrated assemblies that work together as unified connection units. This merging reduces the total number of separate parts and simplifies assembly while maintaining high connection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design ensures the electrical block is securely locked in the electrical box, preventing accidental removal and allowing for adjustment to accommodate varying wall thicknesses, enhancing electrical safety and installation reliability.

Implementation Method 1

at least one tab (20) is adapted to be interposed between the snap-on tab (60) and a rigid part attached to the base (51) of the electrical block (50), wherein said tab (20) is designed to bear, by its inner face, against the snap-on tab (60) in such a way that its outer face forms a stop preventing any inward bending of the snap-on tab (60)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3138167B1Secured assembly electrical apparatus
Publication Date: 2021.06.02 LEGRAND FRANCE SA
  • EP3138167B1 patent drawingFigure 1
  • EP3138167B1 patent drawingFigure 2~4
  • EP3138167B1 patent drawingFigure 5

AI summary

The invention relates to an electrical apparatus (1) to be installed on a wall, comprising: - a support part which is designed to be fixed to the wall and which comprises at least one electric box (80), - an electric unit (50) comprising at least a base (51) which houses an electric mechanism (52) and which is equipped with at least one clip-fastening tab (60) designed to be clipped onto said support part, and - a front part (10, 30) comprising a front wall (11) and at least one tongue (20) which extends to the rear of said front wall so as to fix it to the electric unit. According to the invention, this tongue is designed to fit in between said clip-fastening tab and a rigid part of the base of the electric unit.